diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a03f9900c387ee1b9b3c184e41b6bb460616d94c..18649ede698c6695a8dfe7342fe74da469a99d94 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -235,7 +235,7 @@ running_stage:
       - cd ../sphere
       - echo "Running np_sphere"
       - chmod +x np_sphere
-      - ./np_sphere
+      - OMP_NUM_THREADS=1 ./np_sphere
       - cd ../cluster
       - echo "Running np_cluster"
       - chmod +x np_cluster